====== MC6847T1 ======
Comparison of the MC6847 and MC6847T1 using PRINT CHR$ and direct screen pokes in a loop while in upper and lower code mode.((Also note that the MC6847 and MC6847T1 character bitmap drawing has subtle differences. In particular, note the hash mark and asterisk differences between MC6847 and T1 version.))

^ VDG / MODE ^ PRINT CHR$ ^ SCREEN RAM POKE ^
| MC6847 | {{mc6847chrs.png?direct|}} | {{mc6847poke.png?direct|}} |
| MC6847T1 Uppercase | {{coco2bscreenshotchr1.png?direct|}} | {{coco2bscreenpokes1.png?direct|}} |
| MC6847T1 Lowercase | {{coco2bscreenshotchr2.png?direct|}} | {{coco2bscreenshot2.png?direct|}} |

===== PRINT CHR$ LOOP =====
Simple print chr$ loop:
<code>
10 CLS(0)
20 FOR I=0 TO 255
30 PRINT CHR$(I);
40 NEXT
50 GOTO 50
</code>

===== SCREEN POKE LOOP =====
Simple loop to poke values 0-255 directly into screen RAM: \\
<code>
10 CLS(0)
20 FOR I=0 TO 255
30 POKE 1024+I, I
40 NEXT
50 GOTO 50
</code>

===== MC6847T1 LOWER CASE MODE =====
Put the MC6847T1 into lower case mode:
<code>
1 'http://www.retrogamingtimes.com/magazine/?issue=103&page=203&theme=christmas
10 POKE &H0167,&H39:'put RTS into RVEC3 to skip JMP to CONSOLE OUT
20 POKE &HFF22,&H50:'PIA2 VDG Control - switch in lower with green border
</code>

===== COMPATIBLE SOFTWARE =====
  * Color File II
  * Color Scripsit II
  * Scott Adams adventure games
  * OS-9 Level 1 version 2 I believe did (using XMODE)...
  * NitrOS-9 level 1 for sure does.
  * Both Mikeyterm and Greg-E-Term did as well.

===== RTS =====
Return to [[:Tandy Color Computer:]]